Power transmission system



Oct. 27, 1936. M. KAMPER POWER TRANSMISSION SYSTEM Filed Aug. 15, 1933 5 Sheets-Sheet 1 Oct. 27, 1936. M. KAM'PER POWERv TRANSMISSION SYSTEM Filed Aug. 15, 1933 5 Sheets-Sheet 2 Oct. 27, 1936. M. KAMPr-:R 2,058,802

l POWER TRANSMISSION SYSTEM Filed Aug. 15, 1955 5 sheets-sheet s Oct. 27, 1936.- M. KAMPER POWER TRANSMISSION SYSTEM Filed Aug. 15, 1933 5 sheets-sheet' 4 Oct. 27, 1936. M. KAMPER n PowER'TRANsMIssIoN SYSTEM Filed Aug. l5, 1935 SSheets-Sheet 5 50 f that will render' a change-speed gear suitable for Patented Oct.' 27, 1936l PATENT oFFlcE rowEn TRANSMISSION SYSTEM Mathis Kamper, llallston, near Lcongatha, Australia ApplicationAugust 15, 1933, Serial No. 685,170 In Great Britain August 17, 1932- zo claims. (ci. u sav) The present invention relates to change-speed gearing of the type in which the ratio of the gearing is adapted to be varied automatically in accordance with variation in torque load on the gearing.

The invention is suitable for any form of power transmission system where variation in speed is required in accordance with the load imposed; but it is especially suitable for use in the transmission System of vehicles driven by internalcombustion engines.

An object of the invention is the provision of an improved change-speed gearing of the type set forth, which is reliable in operation and relatively cheap to manufacture.

A further object is to provide an improved change-speed gearing particularly suitable for use in road motor vehicles.

A still further object is to provide an improved change-speed gearing which, while it is capable of being controlled automatically in response to variations in the torque load thereon, is nevertheless adapted for operation in response to iniiuences other than the torque, for instance, at will of an operator for` changing gear under circumstances where the torque control is .unsuitable.

A further object of the invention is to provide a displaceable torque responsive device, the operation of which is directly controlled by the torque of the driven Shaft, and which undergoes step-by-step displacement as lower speed gear ratios are successively engaged under load, and which serves for selectively actuating a series of gear selecting friction clutches connected in parallel between the driving and driven shafts.v

In the form at present preferred, gearing according to the invention comprises a spur-wheel counter-shaft gear box of the constant-mesh type provided with a plurality of gear-Selectingfriction clutches, wherein the counter-shaft is adapted to undergo av limited circumferential displacement about the axis of the aligned input and output Shafts, its position of displacement being automatically determined by the torque reaction, and wherein means are provided whereby the displacement of said counter-shaft serves to actuate said gear-selecting clutches in predetermined sequence. Y

To secure an automatic control characteristic use with an internal-combustionengined vehicle,

it is necessary to employ`control mechanism responsive to the torque existing in the driven shaft of the gearing, in Such manner that the same or Fig. 7 is a diagrammatic elevation of an autosubstantially the same'maximum driving -torque can be applied to the gearing irrespective of thel ratio engaged. As the torque in the output shaft may attain a considerably higher value than the torque of the driving engine, .the problem of 5 providing a torque-responsive device capable of transmitting the whole outputtorque, and which would nevertheless be reliable and Sensitive enough for the object in view, would present considerable difculty. 'I'he present invention 10' provides a way of avoiding this diiculty, since it enables a gearing to be constructed in which the control mechanism is actuated by a device responsive to variation in the torque reaction 'in the gearing, that is, the difference between the input and output torques of the gearing, and not. to variation in the entire output torque. Thus vthe torque reaction acting on the torque-responsive device issubstantially less than the output torque, being in fact zero when a direct drive 20 is established; nevertheless the reaction variesv in the same sense as the output torque, and a gear control device responsive to the reaction can therefore produce a control characteristic which, for the present purpose, is equivalent to the control characteristic that would be given by a device responsive to the output torque alone. The reaction-responsive device, in its preferred form, includes a rocking frame or cage in which the counter-Shaft is mounted, and which is jour- 30 nalled in the gear box so as to be capable of rocking about vthe axis of the aligned input and output shafts, and ,the rocking cage is arranged to actuate, through a' cam, a common control member for operating a nested group of gearselecting clutches, whereby a compact and relatively simple design is obtained.

The invention will be further described with reference to the constructional examples shown in the accompanying drawings, in which: 4o

Fig. 1 is a sectional side elevation of one form of the improved gearing, taken on the line l-I Fig. 2 is a. plan, partly in section taken on the line 2--2 in Fig. 1. 45

Fig. 3 is a sectional end elevation taken on the line 3-3 in Figs. 1 and 2.V

Fig. 4 is a sectional end elevation of which the right-hand half is taken o the line 4R in Fig. 2 and the left-hand half on the line 4L in Fig. 2.

Fig. 5 isa sectional Side elevation of an altern ative arrangement of the clutches.

Fig. 6' is a part sectional plan of the arrangement shown in Fig. 5.

` posed one behind .Secured to the rear ,(that is,

mobile transmission system embodying the gearing shown in detail in Figs. 1 to 6.

Figs. i to 4 show a rthree-speed and reverse gearing for an automobile. Attached tov a driving shaft I, which may be an engine crank-shaft or, as shown in Eig. 'l the driven shaft of an auxiliary clutch device 2, is a built-up clutch driving' body 3 which includes three disk clutches displates constrained to rotate with the clutch body. the side remotel from the driving shaft) of the clutch body 3 is a plate 4 which forms one of the driving plates of the second-gear clutch. The other driving plate of this clutch is formed by an axially slidable annular presser plate 5 which is carried by four or more stepped pins 9 uniformly spaced round the clutch body and slidably fitted in bushes 1 and 8 secured to the plate 4 and the front of the body respectively.

The bottom-gear clutch is disposed immediately in front of the second-gearfclutch, and its two driving plates are formed by an annular disk 9 secured to the body 3 and a presser plate III carried on the pins 6. The top-gear'clutch,`

which is in front of and arranged similarly to the bottom-gear clutch, has a driving disk II and a presser plate I2. The three presser plates i, I0 and I2 are urged towards their respective driving plates 4, 9 and II by series of springs I3, I4 and I5 which react lagainst suitable portionsof the clutch driving element and which are so distributed as to exert a substantially uniforml pressure on the respective friction surfaces.

The three driven plates are o'f the cork-insert type which operate satisfactorily when flooded with oil. The top-gear driven plate I3 is splined to the forward end of a main shaft l1, the nose of which is supported by a spigot bearing I3. The bottom-gear driven plate I9 is iournalled by needle rollers 29 on the boss of the plate I6 and is splined to the forward end of a hollow shaft 2| co-axial with the main shaft I1. 0n the rear of the shaft 2l is formed a bottom-gear driving pinion 22. The second-gear driven plate 23, which is supported with respect to the driving plate 4 and the driven plate I9 by needle rollers 24 and 25 respectively, is splined to the forward end of another hollow shaft 26 co-axial with the shaft I1. On the rear of the shaft 23 is formed a second-gear driving pinion 21. Near-the rear of the main shaft I1 is journalled, by means of .a pair of roller bearings )23 and 29, a main driven gear wheel 30. Disposed between the roller bearings 29 and 29 is a free-wheel device 3| of the wedging roller type, and which serves to traris-v mit torque from the gear wheel 3II to the main shaft I1 in the normal direction of rotation thereof, but allows the main shaft to over-run the gear wheel in the same direction.

The stepped pins 6, which serve to actuate the clutches, are secured to a spider 32 which can be moved towards the clutches by a non-rotatable sleeve 34 acting through a ball thrust bearing 33. The diameter ofthe pins 9 is reduced in three steps, denoted by a, b and c, from rearl to front, the part of largest diameter passing through the bush 1 in the driving plate 4, the part between steps a and b passing through the plates 5 and 9, the part between steps b and c passing through the plates I0 and II, and the part of smallest diameter passing through the plate `I2 and the bush 3 in the body 3. The iongitudinal disposition of the steps is such that, as

the spider and pins `are moved from' their another and having driving' "spigot bearing 1| and it engages with a correspondingly rearmost totheir foremost positions, the clutches are consecutively disengaged inthe order top. second, bottom.

' A live counter-shaft 4l is journalled by bearings 4I and 42 in a cage or frame member adapted to rock through a limited angle about the axis of the main shaft I1. The cage includes a shell 43 to the rear of which is bolted 'a cover 44 provided with a boss 45 journalled in a bearing 46 forming part of the upper portion of the twopart gear casing 4 1. A bearing 43 fitted within the boss 45 supports the rear end of the main shaft I1.` To the front portion 49 of the cage shell 43 is fixed a hollow boss 59 surrounding the co-axial gear shafts and journalled ina bush 5I fixed in the casing 41. A bearing 52 housed in the member 49 supports the second-gear pinion 21, while a bearing 53 housed in the pinion 21 supports the bottom-gear pinion 22.

The frontend ofthe boss i3 terminates in a series of axial cams 34 which co-operate with cams il formed on the rear of the sleeve 34. A pair of levers 53 journalled on a fixed rod 51 are provided with holes I3' .(Flg. 2) in which are fitted apair of pins I3 projectingfrom the sleeve 34. The holes i3' are slightly oval in crosssection, the longer axis of the oval lying longitudinally of the levers to allow for slight relative endwise movement of the levers as they move about the rod l1 as an axis. 'Ihese levers thus serve to prevent thesleeve from rotating while permitting it to slide axially of the gear shafts. 'I'he cams are so shaped that rotation of the rocking cagein a clockwise direction (as viewed in Figs. 3 and 4) imparts a forward displacement to the sleeve 34 and the spider 32. The lower ends of the levers 56 are connected together by a pin 59 behind" which is engaged a lever Il fixed to a control shaft l3| which is journalled in the casing 41 and to which is keyed a control member in the formofapedal32,thispeda1servingasthe drivers clutch-control member.

Fixed to the counter-shaft 43 are a second-gear driven wheel I3 in constant mesh with the pinion 21, and a main gear pinion 34 meshing with the wheel 33. A bottom-gear driven wheel 35, meshing with the pinion 22, is Journalled by bearings I3 and 31 on the counter-shaft and is adapted to be drivably connected thereto by a roller freewheel device 33 arranged to transmit torque fron the wheel to the shaft in their normal direction of rotation, but to allow the shaft to over-run the wheel in the same direction.

The output shaft 33 of the gearing is co-axial with the main shaft I1, being supported b'y a a rear bearing 1I. The forward end of the output shaft is splined, and carries a slined gear wheel 12 which can be slid axially y a control lever 13 (Pigs. 3 and 1) acting through a selector yoke 14 of ordinary design. y

When the wheel 12 is in its foremost position,

splined portion I1a of the main shaft I1 so as to couple the main and output shafts together. As shown in Figs. 1 and 2, the wheel 12 is in a position which provides a neutral" condition of the transmission.

The counter-shaft 4l extends behind the rear bearing 42 and to itsrear endisiixedareverse When the slidable wheel 75 12 is moved to its rearmost position, Ait engages with the wheel 11 and thereby establishes reverse gear.

Means are provided for damping the movement of the counter-shaft cage so as to prevent too violent rocking under sudden variation of driv- 'ing torque and to prevent undesired displacement of the counter-shaft as a result of surges in the l*torque due for example to irregularities in. the

surface of the road on which the vehicle is running. In the example shown the damping mechanism is combined with an auxiliary control spring that is capable of adjustment, to compensate for variation in mechanical condition or adjustment of the driving engine such as valve adjustment, carbureter setting or the like which affect the power output. On the flange of the boss which is fixed to the front of the rockirg cage isformed a toothed sector 80 (Fig. 4) which engages with a rack 8|. To the lower end of the rack is xed a piston 82 fitted in a cylinder 83 fixed to the gear casing 41. To the upper end of the rack is iixed a cupped piston 84 fitted in a cylinder 85, a spring 86 being compressedl between the cylinder head and the piston. The cylinder is screwed into an adaptor |81 fixed to the casing 41 and is thus capable of being raised and lowered to vary the initial compression in the spring 86. A check valve 81 admits lubricating oil from the gear Ibox by a port 88 to the under side of the piston 82 as the rack rises, and a check valve 89 exhausts oil, as the rack falls, by a duct 90 to an adjustable throttle 9| whence the o il is discharged to the upper side of the piston 84, the valve 9| controlling the fall of the rack. As the rack rises, oil above'y the piston 84 fio is exhausted through an adjustable throttle 92 which controls the rise of the rack, the oil being returned to the gear box by a duct 93. It will thus be apparent that the damping mechanism controls the rocking of the counter-shaft cage in both directions, and is moreover capable of primingvitself when necessary.

Where the clutch body 3 is directly connected to the engine crank-shaft. no auxiliary clutch being interposed, the transmission may be operated as follows. Assume that the gear lever 13 is in neutral and that the driving engine is running. In order to start the vehicle from rest, the pedal 62 is fully depressed so as to disengage the three friction clutches. The gearing now comes to rest and the gear lever 13 is moved so as to slide the gear wheel l12 into its forward position, thereby coupling. the main and output shafts together. The driver may nowlcause the vehicle to accelerate gently by partly opening the engine throttle and permitting the pe'dal 62 to rise slowly under the influence of the clutch springs. As a result, rst the bottom-gear clutch engages vand the drive is transmitted through the bottom-gear train 22, 65, the free wheel 68, the counter-shaft 4(|, the main gear train 64, 30, the free wheel 3|, the main shaft I1, the slidable gear wheel 12 (acting as a coupling) and the output shaft |59.` As the pedal rises further, the second-gear clutch engages, and the drive. is transmitted through the second-gear train 21, '63, the counter-shaft 4D, and thereafter as described for bottom gear, the free wheel 68 now over-running. As the pedal` approaches its highest position, the top-gear clutch engages, and

I -wheels 68 and both over-running.

Alternatively, the driver 'may obtain a rapid acceleration from a standstill by allowing the pedal 62 to rise until the bottom-gear clutch is engaged and thereupon opening the engine throttle far enough for the engine to produce a high torque. Now the torque reaction acting on the counter-shaft cage urgesthe cage in a clockwise direction (as viewed in Fig. `4), and fthe equilibrium position of the cage is that in which the axial thrust generated, as a result of torque reaction, by the cams 54, 55 in the sleeve 34 balances the thrust due to the clutch springs. When bottom gear is engaged and the engine is delivering its maximum torque or a relatively high torque, the reaction thrust is suflicient to keep the topand second-gear clutch springs 5 and I3 compressed and thus these clutches are automatically maintained in a disengaged condition so that the driver need no longer control the pedal 62. As the engine speed increases to a high value, its torque falls in characteristic manstrength of the clutch springs and of the adjusting spring 86 are so selected that this fall of torque causes the counter-shaft cage to rock anti-clockwise far enough for the second-gear clutch to be partly engaged. The drive is thereupon partly transferred to the second-gear train 21, 63, the second-gear clutch slipping momentarily. This partial transfer of the drive reduces 'the torque reaction acting on the cage which consequently is rocked still further anticlockwise by the action of the clutch springs and the spring 86 so that the second-gear clutch becomes fully engaged and the drive is automatically transferred to secon-d gear. As the secondgear clutch takes up the entire drive, the engine speed is forcibly reduced to a value corresponding to second gear, and the engine torque thereupon increases to a value suicient to stabilize the counter-shaft cage in its-secondgear position. As the vehicle accelerates further, the change into top gear is effected automatically as soon as the engine torque falls sufficiently to permit the top-gear clutch to engage, the operation being similar to that described with reference to the change from bottom tosecond gear.

Should the driver, after the vehicle has .atfa-ined a certain speed, desire thereafter to accelerate more gently, it is merely necessary for him to close the engine throttle somewhat, and the consequent reduction in torque will automatical'y eiect a changeto a higher gear.

Changes to a lower gear may be made by keeping the throttle open while depressing the pedal 62 farenough to disengage the clutch of the gear on which the 4vehicle is running, whereupon the engine immediately accelerates and the drive is taken up upon synchronism occurring between the driving and driven elements of the free wheel 3| or 68 according to whether second or bottom gear is being established.

Reversing is effected by fully depressing the pedal 62, moving the slidable pinion 12 by means of the lever 13, into engagement with the reverse idler wheel 11, and allowing the pedal to rise far enough to engage the bottomor the second-gear clutch as desired.

When the improved gear is used with an eng'ne of which the torque-speed characteristic curve'has a maximum value at relatively low speed and falls continuously `with increasing speed, the top-gear clutch may be modied so that changes to any lower speed can take place automatically. Such a mod lied arrangement is illustrated in the clutch construction shown in Figs. 5 and 6, in which parts corresponding to those of the construction shown in Figs. 1 to 4 are denoted by the same numerals distinguished by dash suffixes.

The driven plate I0 of the top-gear clutch is Vdisposecybetween a driving plate Il' journalled on aboss III formed on the body 3' and a presser plate i2' which floats on pins Ill fixed to the plate Il. Uniformly spaced around the periphery of the plate il', and pivotally mounted thereon by radial pins Il! are three threearmed levers |03. One arm I of each lever projects forward and is connected to the clutch body by a helical spring III arranged to extend under the influence of driving torque transmitted from the body to the driving plates. A second arm I" passes over the edge of the presser plate l2' and terminates in an inwardly proiecting pin |01 adapted to engage behind the presser plate and urge it forward into engagement with the driven plate It' when the lever is loaded by driving torque. A third arm l, set at about 180 to each of the others, terminates in an outwardly projecting pin il! adapted to be pushed forward by a ring Ill carried by the stepped pins .0 so as to disengage the clutch. A finger HI secured to the clutch body is disposed in the path of the pin |01 at such a point that, when the spring |05 is extended a predetermined distance, thatis, when the torque transmitted by the clutch attains a predetermined maximum, the finger lli will trip the lever Ill andlthus allow the clutch to slip.

The slope of the cams M ness and initial compression of the various clutch control springs may be so selected that, when the vehicle encounters a rising gradient and as the enginespeed, in falling, approaches the point at which the engine develops its maximum torque, the clutch through which the drive is passing automatically begins to slip, and thereby causes the drive to revert automatically to the next lower gear. Furthermore, if, when the vehicle is running at a suitable relatively low speed with top gear engaged and with the throttle only partly open, the throttle is opened fully, the increased torque will cause the top-gear clutch to slip and the gear to be in consequence changed automatically to second vehicle will accelerate rapidly, top gear being eventually re-engaged automatically as previously described.

Where the driving clutch element of the gear is directly connected to the engine crank-shaft, at low speeds it is necessary for the driver to operate the clutch control the vehicle to be started andstopped'or driven at very low speed without risk of stalling the engine, and without the necessity for the driver to operate the clutch control pedal, there may be provided means which automatically disconnect the transmission between the' driving engine and the driven shaft of the system as a result of the speedof the driving engine falling to a particular value. Such means may be provided by a hydraulic coupling of the kinetic type, denoted by 2 in Figa?, having an impeller elementl il! rigidly coupled to the engine crank-shaft il! and a runner element I il arranged to drive the input shaft I of the change speed gearing.` In operating this arrangement, the engine may be allowedto idle with gear; engaged and with-jthe vehicle stationary. the lsiii-l in the hydraulic c ouand 55 and the stiifspeed, whereupon the pedal in order to avoidA risk of stalling the engine. In order to permit Y a,oss,sos

If itis required to start the vehicle on suchy a gradient that the tractive eiiort'required toraccelerate it exceeds that which can be attained when the engine is revolving as fast as is possible with the runner of the hydraulic coupling' stalled, it is necessary for the driver to depress the control pedal, whereupon the vehicle 'will be able to accelerate on a lower gear.

In place ofthe cams 5l, l5 any other suitable means, such as a spiral gear, may be employed for actuating the clutches in response to displacement of the counter-shaft.

I claim:

1. an automatically uname. change-speed,

gearing comprising a gear casing, a driving shaft, a plurality of co-axial gear shafts, a cage member journalled in said casing so as to be capable of rocking about the axis of said gear shafts, a counter-shaft carried by said cage member, a bearing housed in said cage member and serving to support said gear shafts,.a plurality of gear trains connecting said counter-shaft to said gear shafts respectively', a driven shaft coaxial with said gear` shafts, a gear train connecting said counter-shaft to said driven shaft, and means for lectively engaging said' gear shafts with said driving shaft in response to rocking of said cage due to change in torque reaction imposed thereon.

2. An automatically variable change-speed gearing comprising a driving shaft. a main shaft laligned with said driving shaft, a friction clutch 'for establishing a direct drive between said shafts, .a counter-shaft so mounted as to be capablev of circumferential displacement about the axis of said driving shaft, a free wheel clutch, gear trains serving to connect said driving shaft to said main shaft through said counter-shaft and said free wheel clutch, and means for automatically actuating said friction clutch in responsey to displacement of said counter-shaft resulting from variation in torque reaction in said gearing.

3. An automatically variable change-speed gearing comprising a driving shaft, a driven shaft, a plurality of gear-selecting friction clutches having driving elements connected in parallel to said driving shaft and driven Yelements drivably connected in different ratios respectively with said driven shaft, a displaceable reaction member which is capable ofbeing loaded by the diiference between the torques in said driving and-driven shafts, a spring operatively associated with and serving to control thedisplacement of said reaction member, which therefore inidergoes stepby-step displacement as lower speed gear ratios y`are successively engaged under load, and means operatively connected with said reaction member for selectively actuating said clutches.

4. An automatically variable change speed gearing comprising a drivingshaft, a driven e member co-axial with said shaft, a. counter-shaft drivably connected with said driving shaft and driven member by gear trains one of which includes a geai selecting clutch, means operable for disengaging said clutch, said counter-shaft being so mounted as to be capable of circumferential displacement about the axis of said driving shaft,

spring means for resisting displacement of said countershaft, and connecting means between said counter-shaft and said clutch-disengaging means 2,058,802 whereby displacement ofl said counter-shaft serves to actuate said clutch.

5. An automatically variable change speed gearing comprising a gear selecting clutch, an output shaft, a counter-shaft, a gear train serving to connect said counter-shaft to said output shaft, said counter-shaft being displaceable circumferentially about the axis of said output shaft, means whereby displacement of said counter-shaft as a result of variation of load in said gear train serves to actuate said gear selecting clutch, and a damping device of the fluid friction type adapt ed to control both engagement and disengagement of said clutch.

6. An automatically variable change speedv gearing comprising an input shaft, a countershaft so mounted as tobe capable of circumferl ential displacement about the axis of said input shaft, a spring-loaded friction clutch which on engagement serves to establish a direct drive between said input and output shafts, gear trains including a free wheel for connecting said input shaft through said counter-shaft .to said output shaft in a low speed ratio, and means for engaging said clutch automatically in response to displacement of said counter-shaft due to reduction of torque loadingin said gear trains.

7. An automatically variable change-speed gearing comprising an input shaft, an output shaft aligned with said input shaft, a countershaft, gear trains serving to connect said countershaft to said input and output shafts, means for changing the ratio of ksaid gearing, said countershaft being adapted to be displaced automatically in accordance with variation of the torque reaction in said "gearing, and means whereby thedisplacement of said counter-shaft serves to actuate said gear-changing means.

8. An automatically 4variable change-speed gearing comprising an input shaft, an output shaft, a counter-shaft, gear trains serving to connect said input shaft to said counter-shaft and said counter-shaft to said output shaft, said counter-shaft being so mounted that it is capable of displacement as a result of variation in the torque reaction acting thereon, means for disconnecting-the drive through one of said gear trains, and means whereby displacement of said counter-shaft serves to actuate said drive disconnecting means.

9. An automatically variable change-speed gearing comprising coaxial input and outputi shafts, a counter-shaft parallel to said coaxial shafts, gear trains serving to connect said input shaft to said counter-shaft and said countershaft to said output shaft, said counter-shaft being so mounted that it is capable of displacement circumferentially about the axis of said coaxial shafts as a result of variation in the torque reaction acting thereon, a clutch for disconnecting the drive through one of said trains, and means whereby displacement of said countershaft serves to actuate said clutch.

10. An automatically variable change-speed gearing comprising a plurality of coaxial gear shafts, a counter-shaft connected by gear trains to said gear shafts in different ratios, a plurality of gear-selecting clutches associated with said gear shafts respectively, a main shaft coaxial with said gear shafts and connected by a gear train to said counter-shaft, a cage member in which said counter-shaft is journaled and which is capable of rocking about the axis of said gear shafts as a result of variation in torque reaction on the cage, means operable for actuating said clutches in succession, and an operative conrvition between said cage and said clutch actuating means.

l1. An automatically variable change-speed Ythe purpose of actuating said gear selecting clutches, a counter-shaft drivably connected with said gear shafts in different ratios, an output gearing comprising adriving shaft, a plurality of coaxial gear shafts, a plurality of gear-selecting clutches having driving'members connected in shaft drivably connected With said counter-shaft and disposed coaxially with said gear shafts, a

cage member in which said counter-shaft is j'ournaled and which is capable of rocking about the axis of. said gear shafts as a result of variation in torque reaction on'thecage, and an operative connection for transforming the rocking motion of said cage into axial motion of said clutchactuating member. h

12. A power transmission system comprising a driving` shaft, an output shaft, a main gear shaft adapted to transmit torque directly to saidoutput shaft so as to establish a l-to-l gear ratio, means for changing the ratio of said gearing, including a gear-selecting friction clutch for connecting said main gearshaft directly to said driving shaft, means responsive to variation in the difference in the torquesin `said. driving and output shafts, operatively connected with said gear changing means and serving to change the gear ratio automatically, and additional means for automatically disengaging said direct-drive` friction clutch as a result of the torque transmitted thereby rising to a particular value'. l

13. In an automobile driven byV an` internal combustion engine, thecombination of an engine driven shaft, a multi-ratiogearing having an output shaft, a counter-shaft, and gear trains which serve to connect said counter-shaft to said engine driven shaft and said output shaft, means for Vchanging the ratio of said gearing, means responsive to torque reaction in said counter-shaft, op-

eratively connected with said gear changing result of the speed of said engine driven shaft y falling to a particular value. v

14. An automatically variable change-speed gearing comprising a rotatable driving member,

a gear shaft coaxial with said driving member, a

cage member adapted to rock about the axis of said shaft, a counter-shaft carried by said cage member, gear trains which serve to transmit the drive from-said driving member to said countershaft and from said counter-shaft to said gear shaft, clutch mechanism which in one condition establishes a direct drive between said driving member and said gear' shaft and in another condition establishes an alternative ratio through said gear trains and said counter-shaft, and means responsive to rocking of said cage member under torque reaction for changing the condition of said clutch mechanism.

15. An automatically variable change-speed gearing comprising an input shaft, a gear` shaft, a counter-shaft, gear trains connecting said counter-shaft to said input and gear shafts, a spring-loaded gear-selecting friction yclutch in series with said gear trains, means operable for disengaging said clutch, said counter-shaft being so' mounted as to be capable of displacement circumferentially about the axis of said gear shaft under the inuence of increasing torque reaction borne by said counter-shaft, and an operative connection between said counter-shaft and said clutch-disengaging means, whereby said dispiacement of the counter-shaft serves to disensase said clutch.

16. A power-transmission system comprising a rotatable driving member, a gear shaft coaxial with said driving member. a counter-shaft, gear trains serving to connect said driving member through said counter-shaft to said gear shaft in a low speed ratio, gear selecting means operable" for establishing alternatively between said drivyingmember and said gear shaft a direct drive and said lowy speed ratio, said counter-shaft being capable of circumferential displacement about the axis of said gear shaft under the induence of decreasing torquereaction when said low speed ratio is engaged, a connection between said counter-shaft and said gear selecting means whereby said displacement serves to engage direct drive, an engine-driven shaft, and ay hydraulic coupling of the `kinetic type disposed between ,A members of said constant-mesh gear trains, and

an operative connection between said springloaded member and said control means, whereby displacement of said member in consequence of change of torque reaction imposed thereon actuates said clutch control means. .A

18. An automaticallyl variable change-speed gearing comprising'aligned driving'and driven shafts, a constant-mesh gear-train capable of connecting said shafts, selecting means alociated with said gear-train and operable for engaging and said gear-train, a spring-loaded reaction element rotatable about the axis of said shafts and on which is carried an intermediate member of said gear-train, an operative connec tion between said reaction element and said se- 6 lecting means, and a frictional device associated with said reaction element and serving 'to damp oscillations thereof about said axis.

19. Anautomatically variable change speed gearing comprising a driving shaft, a driven shaft y,co-axial with said driving shaft, a plurality 4of gear-selecting friction clutch one of which servesto establish a'direct drive between said shaftsandtheothersofwhichareinseriesrespectively with gear trains of dinerent ratios, each of said gear trains together said shafts through the clutch associated therewith, associated with each of the lower speed ratios a free wheel device, which permits a friction clutch which serves to select a higher speed ratio to 20 transfer the drive from a lower to said higher speed ratio without interruption of the transmission of power from said driving shaft to said driven shaft, a common control member serving on continued displacement in one direction to 25 schiste said friction clutches in succession, and a reaction member loaded by the difference between the torque in said driving and driven shafts for automatically actuating said common control member. 30

20. In an automobile having an internal combustion driving engine, a driving axle, changesp'eed gearing forconnecting said engine to said axle, means operable for varying the ratio of said gearing, a torque-responsive device drivably associated with saiddriving axle and comprising a spring serving to resisttorque loading applied to said device, and an operative connection between said torque-responsive device and said gear changing means, which serves'to vary the gear ratio. automatically, -the provision of an auxiliary spring,alsoservingtoresisttorqueloadingap plied to said device, and means for adjusting the initial-loadappliedbysaidauxiliaryspringto said device. tadjustment lof which serves to vary thlromue values at which gear changing takes p 

